1. Field of the Invention
The invention is related to the field of communications, and in particular, to a processing system that provides integrated ENUM and number portability translations in response to a single signaling message.
2. Description of the Prior Art
A caller places a call to a called party by signaling the E.164 number of the called party to a telecommunication network. The telecommunication network processes the E.164 number to establish a communication path between the caller and the called party. The caller and called party then exchange user communications over the communication path.
If the called party moves to a new location or changes telecommunication networks, the E.164 number may be ported to the new location or network. To port the E.164 number, a Location Routing Number (LRN) for the new location or network is loaded into a Number Portability (NP) database in association with the E.164 number of the called party. The LRN is assigned to a communication node at the new location or network that serves the called party.
After the move, the caller places another call to the called party by signaling the E.164 number of the called party to the telecommunication network. The telecommunication network queries the NP data base with the E.164 number to retrieve the LRN. The telecommunication number then establishes a communication path from the caller to the called party through the communication node based on the LRN. The caller and called party then exchange user communications over the communication path that now passes through the communication node.
More recently, Internet Protocol (IP) networks have implemented Electronic Number Mapping (ENUM) to associate called numbers with call termination instructions specified by the called party. When a caller places a call by specifying the E.164 number of the called party, the ENUM-enabled caller device translates the E.164 number into a Uniform Resource Indicator (URI). The caller device then transfers the URI to the IP network.
The IP network transfers a signaling message indicating the URI to an ENUM database. The ENUM database processes the URI to retrieve a Naming Authority Pointer Resource Record (NAPTR) for the called party. The NAPTR has call termination instructions specified by the called party. These instructions typically comprise a prioritized list of telephone numbers and IP addresses. The ENUM database transfers a signaling message to the IP network indicating the NAPTR. The IP network processes the NAPTR from the signaling message to route the call.
In some ENUM call scenarios, the NAPTR yields an E.164 number. The IP network then routes the call to a telecommunication network based on the E.164 number. The telecommunication network must then transfer another signaling message to an NP database to determine if the E.164 number has been ported. If so, then the NP database transfers a signaling message to the telecommunication network indicating the LRN for the ported number. The telecommunication network then routes the call to the new location or network based on the LRN.
Unfortunately, the current calling scenario requires two separate signaling messages to translate the URI into the LRN—one message to translate the URI into the E.164 number and another message to translate the E.164 number into the LRN. These two messages may delay call set-up to the annoyance of the caller. In addition, the IP network routes the call based on the E.164 before the NP query occurs, so the IP network does not get to route the call based on the LRN. Thus, the call may be routed through an unnecessary network just to obtain the LRN before routing the call to the ported destination.